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Follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are critical for the development and maintenance of germinal centre (GC) and humoral immune responses. Accumulating evidence has demonstrated that the dysregulation of either Tfh cells or Tfr cells contributes to the pathogenesis of autoimmune diseases. We aim to investigate the roles of circulating Tfh cells and circulating Tfr cells in the pathogenesis of primary biliary cholangitis (PBC). A total of 34 patients with PBC and 27 health individuals were enrolled in this study. Flow cytometry revealed that circulating Tfh (CD4+ CXCR5+ CD127hi CD25lo ) cells were increased, but Tfr (CD4+ CXCR5+ CD127lo CD25hi ) cells and ratio of Tfr/Tfh were dramatically decreased in PBC patients compared with healthy controls. The Tfr/Tfh ratio was negatively correlated with level of serum IgM. Meanwhile, we also observed effector memory (CCR7lo PD-1hi ) Tfh cells and Tfr cells were dramatically increased, but central memory (CCR7hi PD-1lo ) Tfh cells and Tfr cells were decreased in PBC patients compared with healthy controls. Effector memory Tfr cells were positively correlated with level of serum ALP. These results indicate that an imbalance of circulating Tfr cells and Tfh cells may be involved in the immunopathogenesis of PBC and may provide novel insight for the development of PBC therapies.

MgH2 nanoparticles were obtained by hydriding ultrafine magnesium particles which were prepared by hydrogen plasma–metal reaction. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the obtained sample is almost pure MgH2 phase, without residual magnesium and with an average particle size of ∼300 nm. Milled with 5 wt.% TiF3 as a doping precursor in a hydrogen atmosphere, the sample desorbed 4.5 wt.% hydrogen in 6 min under an initial hydrogen pressure of ∼0.001 bar at 573 K and absorbed 4.2 wt.% hydrogen in 1 min under ∼20 bar hydrogen at room temperature. Compared with MgH2 micrometer particles doped with 5 wt.% TiF3 under the same conditions as the MgH2 nanoparticles, it is suggested that decrease of particle size is beneficial for enhancing absorption capacity at low temperatures, but has no effect on desorption. In addition, the catalyst was mainly responsible for improving the sorption kinetics and its catalytic mechanism is discussed.